The distributor also houses the centrifugal (term used to refer to two different forces which are related to rotation) advance unit:
This is a set of hinged weights that are attached to the distributor shaft, that will cause the breaker points mounting plate to slightly rotate and then advance the spark timing with higher engine rpm (revolutions per minute).
The distributor also has a vacuum advance unit that will advance the timing even further as a function of the vacuum in the inlet manifold.
There is usually a capacitor (device that stores energy in the electric field), which is also referred to as a condenser is attached to the distributor. You will find that the capacitor is connected parallel to the breaker points, this is to suppress sparking and prevent any wear of the points.
Sometime around the 1970s the primary breaker points were largely replaced with what we call Hall effect sensors. And because this is a non-contacting device and the primary circuit is controlled by solid-state electronics, they eliminated a huge amount of maintenance in point adjustment and replacement. This will now also eliminate any problems with the breaker follower or any cam wear. Therefore, by eliminating a side load it will extend the life of the distributor shaft bearing (component used to reduce friction in a machine).
